JPH06126105A - Organic sewage filtration method and apparatus - Google Patents

Abstract

PURPOSE:To prevent propagation of malodor by sucking a gas from a space part in the upper part of a granular filtering material-filled layer and introducing the gas into the lower part of the filled layer and discharging water in the filled layer through the bottom part of a tank at the time of cleaning the granular filtering material-filled layer, regarding a filtration apparatus for sewage, etc. CONSTITUTION:A blower 8 is operated to suck a gas in the inside of the space B in the upper part of a filtration tank 1, the gas in jetted out of a gas jetting pipe 9 through a gas sucking pipeline 7 and owing to the rising movement of bubbles, a granular filtering material in a filled layer A is stirred, This operation is continued for a prescribed duration. During the time, the generated malodor is circulated only in the closed system and is not released outside. Then, while the blower 8 is kept operating, a valve 12 is opened and water in the filtration tank 1 is drained to the lower part grating. At that time, a valve 13 is opened and outside air is introduced through a gas introducing pipe 14 and the pressure of the tank 1 is prevented from becoming negative and discharging to the discharging pipe 5 is carried out smoothly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is intended to remove SS of organic sewage such as sewage by filtration and to wash the filter layer.
The present invention relates to a novel filtration device and a method for cleaning the same, which prevent odors from being emitted.

[0002]

2. Description of the Related Art Conventionally, a process of precipitating SS in sewage and then biologically treating it has been typical, but the precipitation method has drawbacks such as a low removal rate of SS and a low SS separation rate. Recently, instead of the precipitation method, a method has been attempted in which sewage is supplied to a filtration layer filled with a large granular filter material (hollow plastic granular material, etc.) to remove SS. (Japanese Patent Application Laid-Open No. 2-17908) In this filtration device, the water surface is open to the atmosphere, and in order to wash the filtration layer, air is sent to the lower part of the filtration layer by a blower, and the granular filter medium is agitated by the upward movement of air bubbles. However, the method of draining all the water in the filtration layer is adopted.

When the present inventor re-tested the technique described in the above-mentioned Japanese Patent Application Laid-Open No. 2-17908 for the purpose of treating sewage, a large amount of organic SS was captured in the filtration layer filled with the granular filter medium. However, it was found that when the filter layer was washed with air, a bad odor of H ₂ S, mercaptan, ammonia, etc. was violently emitted to the outside. This phenomenon was particularly severe during the summer when the water temperature was high.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to effectively solve the trouble of generating an offensive odor during washing of a conventional filtration device. As one method, it is naturally conceivable to introduce a bad odor discharged at the time of air-cleaning the filter layer (hereinafter abbreviated as “air-cleaning”) to a separately provided deodorizing device for deodorizing. It has the drawback that expensive equipment such as pipelines is required. An object of the present invention is to very effectively prevent a trouble of generating an offensive odor regardless of such a method.

[0005]

The above-mentioned problems can be effectively solved by the means of the present invention described below. That is, (1) in a method of filtering organic sewage in which sewage is passed through a granular filter medium packed layer provided in a tank, at the time of washing the granular filter medium packed layer, gas is introduced from a space portion provided above the packed layer in a sealable manner. A method for filtering organic sewage, which comprises suctioning and introducing into the lower part of the packed bed, and draining water in the packed bed from the bottom of the tank to wash the packed bed. (2) A granular filter medium filling layer is provided below the water surface in the tank, a closed space portion capable of introducing outside air is provided above the water surface, gas is sucked from the space portion, and gas from the space portion is discharged below the filling layer. An apparatus for filtering organic wastewater, comprising a flow passage and a gas discharge pipe, a blower provided in the flow passage, and a drainage portion provided at the bottom of the tank. Is.

(Structure) An example of the structure of the present invention will be described below with reference to FIG. However, the present invention is not limited to the following examples. In FIG. 1, 1 is a filtration tank, and the tank 1 has a packed bed A filled with a granular filter medium. As the granular filter medium, one having a specific gravity that is easily disturbed during washing with air is preferable, and its material, shape and particle size are appropriately selected depending on the properties of the sewage to be treated. For example, a preferable particle size for sewage is 10-30
A hollow plastic filter material having a diameter of mm can be used.

An inflow portion 2 of organic waste water is provided below the packed bed A in the tank 1, and a filtered water outflow portion 3 is provided above the bed A. The position of the filtered water outflow portion 3 is provided. The water surface 4 of the tank 1 is determined by this. A watertight space B having a cover 6 is provided above the water surface 4 of the tank 1, and the space B is connected to a blower (blower) 8 via a gas suction pipe line 7 and a gas suction pipe line. It is connected to a gas discharge pipe 9 through which gas is blown into the tank 1. An upper porous member (grating) 10 and a lower porous member 11 which respectively prevent the outflow of the granular filter medium are stretched above and below the packed bed A. A drain portion 5 having a valve 12 is provided at the bottom of the tank, and a gas inflow pipe 14 having a valve 13 for allowing outside air to flow into the space B is provided at the top of the tank (cover 6). The gas inflow pipe 14 is a pipe that plays an important role in the filtration method of the present invention. The height of the space B may be such that water does not enter the gas suction conduit 7 when the blower 8 is started, and the height thereof is not particularly limited.

In the filtration tank of the present invention having the above-mentioned constitution, the wastewater is filtered by the upward flow without air diffusion during the operation for normal filtration. Then, as the filter device of the present invention is operated to filter the wastewater, SS in the organic wastewater is filtered in the packed bed A, and filtered water having SS of 30 mg / liter or less is obtained. Since a large amount of SS will leak into the filtered water when the filtration is continued for a long time, the supply of the organic wastewater is stopped at this point, and the emission of the malodor is prevented by the method unique to the present invention described in the following action. Meanwhile, the packed bed A is washed.

(Operation) A method of cleaning the packed bed A of the filtration tank 1 of the present invention will be described with reference to FIG. 1) Drive the blower 8 to suck the gas in the space B,
The gas is ejected from the gas discharge pipe 9 into the tank 1, and the granular filter medium in the packed bed A is violently disturbed by the ascending movement of the bubbles. Continue this operation for a few minutes. At this time, a bad odor is released from the packed bed A, but the gas discharged from the gas discharge pipe 9 by the blower 8 rises in the packed bed A, reaches the space B, and passes through the gas suction conduit 7 again. Since it is sucked into the blower 8 and circulated, no bad odor is leaked to the outside. This is one of the main points of the present invention, and conventionally, there is no example of cleaning the filtration layer while circulating the gas in this way.

2) While the blower 8 is still driven, the valve 12 is opened and the water in the filtration tank is drained to the lower grating 11 to discharge the SS trapped in the packed bed A out of the tank. The outside air introduction passage 14 plays an important role in this operation. If the outside air introducing passage 14 does not exist, even if the valve 13 is opened, the inside of the tank will have a negative pressure, and drainage cannot be performed at all, so that the packed bed A cannot be washed. When the valve 13 is opened while driving the blower 8, the water in the filtration tank is drained, but the outside air having a volume equal to the amount of the drained water is introduced into the outside air introduction passage 1
Since it flows into the tank 1 from 4, the inside of the tank 1 does not become a negative pressure, and smooth drainage is possible from the pipeline of the drainage section 5. It is preferable that the drainage be performed rapidly. Then, after the drainage is completed, the blower 8 is stopped, the valve 12 is closed, and the operation 2) is completed.

As described above, the filling layer A can be washed without releasing a bad odor to the outside. The filtered water outflow portion 3 may also serve as the outside air introduction passage without providing the outside air introduction passage 14 in the closed cover portion 6. That is, when the valve 12 is opened and drained, outside air may flow in through the filtered water outflow passage 3. Then, again organic sewage 2
When water is supplied and the filtration process is restarted, the water level in the tank 1 rises little by little, and the gas in the tank 1 is gradually discharged to the outside through the outside air introduction passage 14, but the amount is small. Therefore, it can be easily disposed of in any way. For example, in the subsequent step of the filtration step of the present invention, a biological treatment facility such as activated sludge treatment is usually provided, but with a large amount of air by introducing a small amount of the aforementioned malodorous gas into a blower chamber that performs aeration of this activated sludge treatment, It is rational to send it to the aeration tank to deodorize the organisms.

[0012]

【The invention's effect】

(1) The organic SS in the organic wastewater can be effectively removed by filtration, and the odor does not diffuse to the outside even when the filtration layer is washed. Therefore, no special deodorizing equipment is required, which is extremely rational. (2) Since the malodor does not diffuse to the outside, the filtration layer can be washed with a sufficient amount of gas. (In the past, since the filter layer was washed with air, there was a drawback that the same amount of malodorous gas as the amount of washing air used was discharged outside the system.)

[Brief description of drawings]

FIG. 1 is an explanatory sectional view of a device showing the operation of the filtration device of the present invention.

[Explanation of symbols]

 1 Filter Tank 2 Organic Sewage Inflow Portion 3 Filtered Water Outflow Portion 4 Tank Internal Water Surface 5 Drainage Portion 6 Cover 7 Gas Suction Pipeline 8 Blower 9 Gas Discharge Pipe 10 Upper Porous Member 11 Lower Porous Member 12 Valve 13 Valve 14 Gas Inflow pipe A Packed bed B Space

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8925-4D B01D 29/08 Z

Claims (2)

[Claims] 1. A method for filtering organic sewage in which sewage is allowed to pass through a granular filter medium packed layer provided in a tank, wherein a gas is introduced from a space that is hermetically sealed above the granular filter medium packed layer when the granular filter medium packed layer is washed. A method for filtering organic sewage, which comprises suctioning and introducing into the lower part of the packed bed, and draining water in the packed bed from the bottom of the tank to wash the packed bed. 2. A granular filter medium filling layer is provided below the water surface in the tank, and a closed space portion capable of introducing outside air is provided above the water surface. Gas is sucked from the space portion and gas from the space portion is provided below the filling layer. A filter device for organic wastewater, comprising a flow passage for discharging and a gas discharge pipe, a blower provided in the flow passage, and a drainage portion provided at the bottom of the tank.